A new countercurrent chromatography instrument, the cross-axis flow-through coil planet centrifuge is proposed for the preparative chromatography of peptides. This is an apparatus that separates substances according to their partitioning in a liquid-liquid equilibration system without the use of a solid-phase support. The instrument will be tested in the purification of large quantities of synthetic peptides, using different conditions and solvent systems to achieve high resolution and recovery. The successful development of this instrument would make available a lower cost technology for chromatographic purification.